Mason sand is a fine white sand with several applications. Play sand is another name for this sand. It is used in building mortar as a fine aggregate. It is also a concrete mortar mix. Double-screened fine sand is what washed mason sand is. In fact, mason sand can be used as a sand base for above-ground pools, as well as for playground areas and sand volleyball courts. https://texasgardenmaterials.com/product/mason-sand-price-cubic-yard/